Question for those who have used Zyban or Chantix

Im on my 5th day quit,Herbal cigarettes, but I'm having a lot of problems with depression, anxiety, and irritability/frustration. I really, really want to maintain this quit and I should be happy that I'm doing it. Check that, I *am* happy that I'm doing it... but I'm not happy about *anything* else. I've had a few failed quits in the past and it hasn't been this bad. So, I talked to my doctor on the phone and he's thinking of either Zyban or Chantix for me. My appointment isn't until the 16th and I'm just hanging in (tooth and nail) until then. I know that these symptoms usually come with quitting. I've had them before,stop smoking, just not to this extent. I can handle it most of the day, but I'm barely functional in the evenings. I'm curious if anyone that has tried either of those meds noticed that they helped with any of these problems? Is one more geared to help with this than the other? My doctor has never smoked and I'd love to have some imput from experience. I'm researching as much as I can, but textbook info just isn't the same as experience.I'd really appreciate any input at all. Thanks!